The evolution of psychopathology includes study of its onset, course, and endpoints at the level of symptom, syndrome, and disorder. It is best conducted with a sample drawn from the general population. A cohort of 3481 individuals from the Baltimore ECA site, originally a probability sample of residents of Eastern Baltimore over 18 years of age in 1981, is now entering the middle and later years of life. The goals of this research are: (1) estimation of incidence, and expanded study of risk factors, for psychopathology; (2) description of patterns of remission, and risk factors for continuation; (3) assessment of potential endpoints in terms of mortality and morbidity due to illnesses of middle and later life such as heart disease and cancer; (4) focussed study of the risk for onset of cognitive impairment; and (5) search for syndromes of depression which depart from the DSM-III configuration and are important in the elderly. More than 95% of the original cohort will be traced. For the projected 620 deceased subjects, death certificates will be obtained. At least 85% of those traced will be personally interviewed with measures including the DIS-III-R, and others used in 1981 and 1982. New cases over the eleven year follow-up, and a sample of non-cases, will be examined by psychiatrists using the SCAN. A variety of analytic techniques will be used, including estimation of weights to permit adjustment for differential attrition by age, sex, and race. There will be intensive efforts to stimulate accurate recall of symptomalogy. This project will provide the highest quality estimates of incidence of mental disorders yet obtained. New insights into the relationship between psychopathology and cognitive impairment in the elderly will be uncovered. The project will be the only population-based study of the effect of specific mental disorders on later occurrence of important physical illnesses. Heretofore unknown predictors of continuation and termination of psychopathology in the middle part of the life span will be described.